High voltage feedthrough for ion pump

Abstract

Ion pump (10) has feedthrough (33) for electrical connection to anode post (32) within the pumping chamber. Opening (36) in the pumping chamber wall receives a portion of insulator (42). The insulator (42) has a flange (48) which is of larger diameter than the opening (36) so that sputtered cathode material cannot directly disposit on the outer and upper surfaces of the flange (48).

What is claimed is: 
     
       1. An ion pump comprising: an ion pump body, said body having a pumping chamber therein, a vacuum connection to said pumping chamber so that said pumping chamber can be connected to a volume to be pumped, a cathode within said pumping chamber, a feedthrough opening in said body;   an anode within said pumping chamber, a post on said anode, said post extending through said feedthrough opening for support and electrical connection of said anode;   a tubular ceramic insulator bushing forming a feedthrough insulator, said bushing having an exterior wall and an interior wall, a portion of said exterior wall being sealed to said ion pump body and a portion of said interior wall being sealed to said post to provide vacuum integrity to said pumping chamber, said exterior wall of said ceramic bushing including a radially outwardly projecting annular flange extending radially exteriorly of said feedthrough opening in said body, the space radially exteriorly of said annular flange being exposed to the vacuum of said vacuum chamber, said annular flange having an exterior lateral surface extending completely around said insulator bushing and which is not visible through said feedthrough opening in said body so that said exterior surface extending completely around said insulator bushing is not in a direct sputtering line from said cathode.   
     
     
       2. The ion pump of claim 1 wherein said flange has a larger diameter than said feedthrough opening in said body so that the exterior surface of said radially outwardly projecting annular flange on said ceramic tubular insulator is not visible from said pumping chamber. 
     
     
       3. The ion pump of claim 2 wherein said tubular insulator bushing and said feedthrough opening in said body define figures of revolution around the axis of said post on said anode, and said post on said anode extends into the tubular interior of said ceramic insulator bushing. 
     
     
       4. The ion pump of claim 3 wherein said post is sealed to a cup, and said cup is sealed to the interior of said ceramic insulator bushing adjacent the pumping chamber end thereof. 
     
     
       5. The ion pump of claim 4 wherein said insulator bushing is sealed to said body by means of a cup which is sealed to said body radially outwardly from said flange and is sealed to the exterior surface of said insulator bushing beyond said flange with respect to said pumping chamber 
     
     
       6. A high voltage feedthrough comprising: a chamber in which sputtering occurs and having an opening in a wall thereof;   a tubular insulator having a projecting portion thereof positioned on the side of said opening away from said sputtering chamber, which portion extends completely around said tubular insulator and is not visible from said sputtering chamber;   a first cup secured to the exterior of said tubular insulator beyond the side of said portion away from said opening and sealed to said wall to provide a vacuum seal around the exterior of said tubular insulator, a connector extending from said sputtering chamber into the interior of said tubular insulator for electrical connection to an electrical device within said sputtering chamber; and   a second cup sealed to said connector and to said tubular insulator for providing a vacuum seal through the interior of said tubular insulator.   
     
     
       7. The high voltage feedthrough of claim 6 wherein said opening is a circular opening and said projecting portion is a radially outwardly projecting angular flange substantially coaxial with said circular opening so that the outer lateral surface of said flange is not visible through said circular opening. 
     
     
       8. The high voltage feedthrough of claim 7 wherein said chamber is the pumping chamber of an ion pump, and said feedthrough provides an anode connection for said ion pump.